Propoxylated PTB coalescing agents for water-borne protective coatings

Abstract

Versatile coalescing agents for water-borne coating applications are disclosed. The coalescents comprise propoxylated propylene glycol tert-butyl ether and one or more organic solvents, particularly glycol ethers. These coalescents efficiently reduce minimum film-forming temperature, and also have a dramatically reduced tendency to swell resins compared with prior art coalescents.

We claim: 
     
       1. A versatile coalescing agent for use in water-borne coatings that have good film-forming characteristics and rapid hardness development upon application, said coalescing agent comprising: (a) from about 1 to 10 weight percent of one or more propylene oxide adducts of propylene glycol tert-butyl ether having the formula: ##STR6##  wherein n is an integer from 2 to 6, and A is an oxypropylene unit; and (b) from about 90 to 99 weight percent of an organic solvent selected from the group consisting of alcohols, glycols, glycol ethers, glycol ether esters, ketones, esters, aliphatic and aromatic hydrocarbons, halogenated hydrocarbons, nitriles, amides, and carbonates.   
     
     
       2. The composition of claim 1 wherein n=2. 
     
     
       3. The composition of claim 1 wherein the organic solvent is a glycol ether is selected from the group consisting of propylene glycol tert-butyl ether, propylene glycol n-butly ether, propylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol phenyl ether. 
     
     
       4. The composition of claim 1 wherein n=2 and the organic solvent is a glycol ether, said glycol ether being propylene glycol tert-butyl ether.